A pole-housing device for monkeys and other nonhuman primates was disclosed in U.S. Pat. No. 4,685,424. In that disclosure Migler described a means of housing nonhuman primates by tethering each monkey to a ring mounted on a pole. The ring is free to slide up and down the pole allowing the nonhuman primate to climb up and down the pole. Other nonhuman primates are similarly attached to adjacent poles spaced so that the collars of adjacent nonhuman primates cannot extend past each other. This allows close physical contact and social interaction without the danger of entanglement of the tethers of adjacent nonhuman primates. Since there are no external walls to the device the invention is suitable only for nonhuman primates that are not aggressive toward their human caretakers, since an aggressive nonhuman primate would be able to attack the caretaker.
This difficulty was overcome by Migler in U.S. Pat. # 4,736,709. In this patent Migler described a means of enclosing a pole-housing device in such a way that a number of such devices could be placed side by side with the internal walls separating the nonhuman primates removed, while the external walls remained in place. This provided protection to the caretakers, while still allowing climbing and social interaction between the nonhuman primates.
While this modification solved the problem of safety for the caretaker, it did not solve the problem of the absence of a squeeze-back mechanism. Individual cages for nonhuman primates usually have a movable rear wall which, when pulled forward by arms that project through the front wall, squeezes the nonhuman primate against the front wall of the cage, holding the nonhuman primate there, and allowing an injection to be given through the bars of the front wall, or for other purposes. This mechanism is called a squeeze-back. This type of squeeze-back can be described as having a "U" shape, with the long arms of the "U" representing the long arms that project through the front of the cage and the horizontal section of the "U" representing the moveable rear wall.
The pole-housing devices described above does not include a squeeze-back. The combination of a squeeze-back of the type found in individual cages, with the existing pole-housing devices would not solve the problem of squeezing large nonhuman primates. In the case of the original pole-hosing device, there are no walls to squeeze the nonhuman primate against. In the case of the modified pole-housing device described in U.S. Pat. # 4,736,709, which does have walls, the poles are mounted in the interior of the device and would block the movement of the "U"-shaped squeeze-back toward the walls if the squeeze-back was installed between the poles; that is, the nonhuman primate could avoid being squeezed by positioning itself between a pole and the wall. If the squeeze-back was installed between the pole and the wall the nonhuman primate could escape being squeezed by positioning itself between the poles.
The solution to the problem, as taught here, is provided by mounting the poles in the wall (or perimeter) of the device. This permits the installation of a squeeze-back between poles on opposite walls of the device. The design of the squeeze-back may be a "U"-shape as is found in conventional individual cages. Two such "U"-shaped squeeze-backs would be needed, one that would slide towards the front wall and the other towards the rear wall. However, I teach a more efficient design, more suitable for pole-housing, having the shape of the capital letter "H". In this case only a single squeeze-back is needed. The "H"-shaped squeeze-back can be moved in either direction, that is, toward the front or rear, to squeeze a nonhuman primate against the front or rear wall. The "H"-shaped squeeze-back is adapted to permit movement towards the front or rear wall, to squeeze a nonhuman primate against the front or rear wall.
Another problem to be overcome in pole-housing is the difficulty in catching a nonhuman primate that is tethered to a pole. Nonhuman primates that are small may be caught with a gloved hand, but larger nonhuman primates, and in particular nonhuman primates with large canine teeth are too dangerous to be caught with a gloved hand and a safer means is needed. The present invention overcomes this difficulty by the use of a door adjacent to the pole, with a gap between the door and pole, such that the tether may be pulled out through the gap, connected to a tether-holder, disconnected from the sliding ring on the pole, and the door opened, allowing the nonhuman primate to be removed from the device, held securely at the end of the tether holder and away from the caretaker.
Another problem is the difficulty in grasping a nonhuman primate that is tethered to a pole. The squeeze-back that is built into the pole-housing device disclosed above does not provide a safe means of grasping a nonhuman primate. If the nonhuman primate is squeezed against the front wall and the door is opened in order to grasp the nonhuman primate the caretaker would probably be bitten by the nonhuman primate unless it is in a favorable position facing away from the caretaker. Also, if the nonhuman primate was squeezed against the door, then the door could not be opened to grasp the nonhuman primate. The present invention overcomes this problem in two ways. The first solution is by the use of a portable squeeze-back, which provides convenient and relatively safe access to the rear of the nonhuman primate once it has been squeezed against the wall. The second solution is by the use of a horizontal slot in the wall or door of the device. With this solution the tether is disconnected from the sliding ring, slid into the slot, and the tether is pulled out, forcing the nonhuman primate up against the wall or door. The door is then opened and the monkey is grasped.
This invention also includes several embodiments of the sliding ring and pole allowing alternative means of removing a nonhuman primate from a pole.
These inventions were disclosed by Migler in Disclosure Document numbers 187590, 193841, and 213052 of the Disclosure Document Program of the U.S. Patent Office.